Enzymatic hydrolysis of proteins can enhance their emulsifying properties and antioxidant activities.However,the problem related to the hydrolysis of proteins was the generation of the bitter taste.Recently,high hydro...Enzymatic hydrolysis of proteins can enhance their emulsifying properties and antioxidant activities.However,the problem related to the hydrolysis of proteins was the generation of the bitter taste.Recently,high hydrostatic pressure(HHP)treatment has attracted much interest and has been used in several studies on protein modification.Hence,the study aimed to investigate the effects of enzymatic hydrolysis by Corolase PP under different pressure treatments(0.1,100,200,and 300 MPa for 1-5 h at 50℃)on the emulsifying property,antioxidant activity,and bitterness of soybean protein isolate hydrolysate(SPIH).As observed,the hydrolysate obtained at 200 MPa for 4 h had the highest emulsifying activity index(47.49 m^(2)/g)and emulsifying stability index(92.98%),and it had higher antioxidant activities(44.77%DPPH free radical scavenging activity,31.12%superoxide anion radical scavenging activity,and 61.50%copper ion chelating activity).At the same time,the enhancement of emulsion stability was related to the increase of zeta potential and the decrease of mean particle size.In addition,the hydrolysate obtained at 200 MPa for 4 h had a lower bitterness value and showed better palatability.This study has a broad application prospect in developing food ingredients and healthy foods.展开更多
Objective Bladder outlet obstruction(BOO)results in significant fibrosis in the chronic stage and elevated bladder pressure.Piezo1 is a type of mechanosensitive(MS)channel that directly responds to mechanical stimuli....Objective Bladder outlet obstruction(BOO)results in significant fibrosis in the chronic stage and elevated bladder pressure.Piezo1 is a type of mechanosensitive(MS)channel that directly responds to mechanical stimuli.To identify new targets for intervention in the treatment of BOO-induced fibrosis,this study investigated the impact of high hydrostatic pressure(HHP)on Piezo1 activity and the progression of bladder fibrosis.Methods Immunofluorescence staining was conducted to assess the protein abundance of Piezo1 in fibroblasts from obstructed rat bladders.Bladder fibroblasts were cultured under normal atmospheric conditions(0 cmH_(2)O)or exposed to HHP(50 cmH_(2)O or 100 cmH_(2)O).Agonists or inhibitors of Piezo1,YAP1,and ROCK1 were used to determine the underlying mechanism.Results The Piezo1 protein levels in fibroblasts from the obstructed bladder exhibited an elevation compared to the control group.HHP significantly promoted the expression of various pro-fibrotic factors and induced proliferation of fibroblasts.Additionally,the protein expression levels of Piezo1,YAP1,ROCK1 were elevated,and calcium influx was increased as the pressure increased.These effects were attenuated by the Piezo1 inhibitor Dooku1.The Piezo1 activator Yoda1 induced the expression of pro-fibrotic factors and the proliferation of fibroblasts,and elevated the protein levels of YAP1 and ROCK1 under normal atmospheric conditions in vitro.However,these effects could be partially inhibited by YAP1 or ROCK inhibitors.展开更多
Response surface methodology (RSM) was employed in the present work and a second orderquadratic equation for high hydrostatic pressure (HHP) inactivation was built. Theadequacy of the model equation for predicting the...Response surface methodology (RSM) was employed in the present work and a second orderquadratic equation for high hydrostatic pressure (HHP) inactivation was built. Theadequacy of the model equation for predicting the optimum response values was verifiedeffectively by the validation data. Effects of temperature, pressure, and pressureholding time on HHP inactivation of Escherichia coli ATCC 8739 were explored. Byanalyzing the response surface plots and their corresponding contour plots as well assolving the quadratic equation, the optimum process parameters for inactivation E. coliof six log cycles were obtained as: temperature 32.2℃, pressure 346.4 MPa, and pressureholding time 12.6min.展开更多
Trimethylamine N-oxide(TMAO)is one of the most important nutrients for bacteria in the deep-sea environment and is capable of improving pressure tolerance of certain bacterial strains.To assess the impact of TMAO on m...Trimethylamine N-oxide(TMAO)is one of the most important nutrients for bacteria in the deep-sea environment and is capable of improving pressure tolerance of certain bacterial strains.To assess the impact of TMAO on marine microorganisms,especially those dwelling in the deep-sea environment,we analyzed the bacterial community structure of deep-sea sediments after incubated under different conditions.Enrichments at 50 MPa and 0.1 MPa revealed that TMAO imposed a greater influence on bacterial diversity and community composition at atmospheric pressure condition than that under high hydrostatic pressure(HHP).We found that pressure was the primary factor that determines the bacterial community.Meanwhile,in total,238 bacterial strains were isolated from the enrichments,including 112 strains a ffiliated to 16 genera of 4 phyla from the Yap Trench and 126 strains a ffiliated to 11 genera of 2 phyla from the Mariana Trench.Treatment of HHP reduced both abundance and diversity of isolates,while the presence of TMAO mainly af fected the diversity of isolates obtained.In addition,certain genera were isolated only when TMAO was supplemented.Taken together,we demonstrated that pressure primarily defines the bacterial community and culturable bacterial isolates.Furthermore,we showed for the first time that TMAO had distinct influences on bacterial community depending on the pressure condition.The results enriched the understanding of the significance of TMAO in bacterial adaptation to the deep-sea environment.展开更多
As a non-thermal processing technology,high hydrostatic pressure(HHP)can be used for starch modification without affecting the quality and flavour constituents.The effect of HHP on starch is closely related to the tre...As a non-thermal processing technology,high hydrostatic pressure(HHP)can be used for starch modification without affecting the quality and flavour constituents.The effect of HHP on starch is closely related to the treatment time of HHP.In this paper,we investigated the impacts of HHP treatment time(0,5,10,15,20,25,30 min)on the microstructure,gelatinization and thermal properties as well as in vitro digestibility of oat starch by scanning electron microscopy,X-ray diffraction,Fourier transform infrared spectroscopy,13C NMR and differential scanning calorimeter.Results showed that 5-min HHP treatment led to deformation and decreases in short-range ordered and doublehelix structures of oat starch granules,and further extending the treatment time to 15 min or above caused the formation of a gelatinous connection zone,increase of particle size,disintegration of short-range ordered and double-helix structures,and crystal structure change from A type to V type,indicating gelatinization occurred.Longer treatment time also resulted in the reduction in both the viscosity and the stability of oat starch.These indicated that HHP treatment time greatly influenced the microstructure of oat starch,and the oat starch experienced crystalline destruction(5 min),crystalline disintegration(15 min)and gelatinization(>15 min)during HHP treatment.Results of in vitro digestibility showed that the rapidly digestible starch(RDS)content declined first after treatment for 5 to 10 min then rose with the time extending from 15 to 30 min,indicating that longer pressure treatment time was unfavourable to the health benefits of oat starch for humans with diabetes and cardiovascular disease.Therefore,the 500-MPa treatment time for oat starch is recommended not more than 15 min.This study provides theoretical guidance for the application of HHP technology in starch modification and development of health foods.展开更多
Three mutants of rice (Oryza sativa L. ), Mutant 1, Mutant 2 and Mutant 3, which were selected by high hydrostatic pressure (75 MPa), and their parent Yuexiangzhan were used to study the changes in chlorophyll fluores...Three mutants of rice (Oryza sativa L. ), Mutant 1, Mutant 2 and Mutant 3, which were selected by high hydrostatic pressure (75 MPa), and their parent Yuexiangzhan were used to study the changes in chlorophyll fluorescence during different growth stages. In all the three mutants, the function of PSⅡ was improved, F_v/F_m ratio of mutants increased compared to their parent at tillering and heading stage, and ΦPSⅡ also improved except for Mutant 2 at heading stage. Similar to their parent, the mutants exhibited slight photoinhibition at noon and almost complete recovery to initial levels of 6:00 after 18:00 at heading stage. At milking stage, the photoinhibition in the mutants was obvious, and recovered rapidly compared to the parent. Yields of individual plant and grain/straw ratio were also higher in three mutants than the parent. Results indicated that characteristics of chlorophyll fluorescence in leaves of mutants and their photoinhibition in the field had changed. It is suggested that high hydrostatic pressure induction could be applied as a new effective approach in high-yield rice breeding in the future.展开更多
High hydrostatic pressure（HHP） processing is applied to a Konjac glucomannan（KGM）-casein（CS） mixture to explore the changes in the mixture＇s properties and microstructures.The mixture＇s viscosity increases by ...High hydrostatic pressure（HHP） processing is applied to a Konjac glucomannan（KGM）-casein（CS） mixture to explore the changes in the mixture＇s properties and microstructures.The mixture＇s viscosity increases by -18.1% at low HHP（200 MPa） and decreases by about 5.3-31.7% at high HHP（600 MPa）.Scanning electron microscopy analysis shows that low HHP induces a denser and more compact structure,and high HHP leads to a porous and reticular structure.X-ray diffraction shows that the mixture is amorphous without dramatic changes; only some small crystalline peaks appear under excessive pressure.Fourier transform infrared analysis indicates that the non-covalent interactions（hydrogen bonds,etc.） are probably the most important factors for the modification of mixture properties.Bonding enhances under low pressure,and weakens with increasing pressure and time.展开更多
The effects of high hydrostatic pressure （HHP） treatment on sea cucumber qualities, such as shelf-life, autoenzyme, total volatile basic nitrogen （TVB-N）, mucopolysaccha ride and protein, were investigated experim...The effects of high hydrostatic pressure （HHP） treatment on sea cucumber qualities, such as shelf-life, autoenzyme, total volatile basic nitrogen （TVB-N）, mucopolysaccha ride and protein, were investigated experimentally. The shelf-life of sea cucumber was greatly prolonged by HHP treatment. High pressure treatment of sea cucumber significantly reduced the activity of autoenzyme at 550 MPa. The TVB-N content was 8.4 mg/100 g in the HHP-treated samples after 38 days＇ storage at 4 ~C, while it had already reached 11.2 mg/100 g in the untreated ones after 5 days＇ storage under the same condition. The relative mucopolysaccharide content of the HHP-treated samples was 94.3%, while that of the heat-treated ones was only 35.5%. The sodium dodecyl sulfate polyacrylamide gel electrophoresis （SDS-PAGE）, Differential scanning calorimetric （DSC）, ANS fluorescence probe method and fourier-transform infrared （FTIR） spectroscopy results indicated some changes in protein subunits, denaturation, surface hydrophobicity and secondary structure of sea cucumber protein. This study has provided complementary information of pressure-induced structural changes on both the molecular and the sub-molecular level of sea cucumber protein.展开更多
The influences of ultra-high hydrostatic pressure treatment on foaming and physical properties (solubility, hydrophobicity and sulfhydryl content) of egg white were investigated. A pressure range of 0-500 MPa, time ra...The influences of ultra-high hydrostatic pressure treatment on foaming and physical properties (solubility, hydrophobicity and sulfhydryl content) of egg white were investigated. A pressure range of 0-500 MPa, time range of 0-20 min and pH range of 7.5-8.5 were selected. The foaming property of egg white is improved by 350Mpa and 10min. The treatment resulted in in- crease of sulfhydryl content of egg white, while solubility and hydrophobicity were significantly decreased.展开更多
Alaska pollock is an important protein source which is extensively used in the food industry. Pollock protein isolates(PPI) with significantly enriched protein contents could be prepared using isoelectric solubilizati...Alaska pollock is an important protein source which is extensively used in the food industry. Pollock protein isolates(PPI) with significantly enriched protein contents could be prepared using isoelectric solubilization/precipitation(ISP) processing; however, the functional properties of this process is limited by the large amount of water-insoluble proteins. In this study, we investigated the influence of high hydrostatic pressure(HHP) treatment on the solubility and structural changes of PPI. PPI obtained using ISP is treated with hydrostatic pressures of 200, 300, 400, and 500 MPa for up to 15 min, and the HHP-treated samples were observed to exhibit significantly improved solubilities. Further biochemical assays reveal that the continuous HHP treatments reduce the contents of free sulfhydryl groups and promote the formation of macromolecules with better water solubilities, which may induce the solubility improvements of the HHP-treated PPI. Our results indicate that HHP can be utilized to effectively prepare highly water-soluble Alaska pollock protein in food processing.展开更多
The changes in the crystal structures of synthetically prepared amorphous calcium phosphate（ACP） and hydroxyapatite（HAP） in water（1：1 mass ratio） were studied by synchrotron X-ray diffraction（XRD） under ultra...The changes in the crystal structures of synthetically prepared amorphous calcium phosphate（ACP） and hydroxyapatite（HAP） in water（1：1 mass ratio） were studied by synchrotron X-ray diffraction（XRD） under ultra-high hydrostatic pressures as high as 2.34 GPa for ACP and 4 GPa for HAP. At ambient pressure, the XRD patterns of the ACP and HAP samples in capillary tubes and their environmental scanning electron micrographs indicated amorphous and crystalline characteristics for ACP and HAP, respectively. At pressures greater than 0.25 GPa, an additional broad peak was observed in the XRD pattern of the ACP phase, indicating a partial phase transition from an amorphous phase to a new high-pressure amorphous phase. The peak areas and positions of the ACP phase, as obtained through fitting of the experimental data, indicated that the ACP exhibited increased pseudo-crystalline behavior at pressures greater than 0.96 GPa. Conversely, no structural changes were observed for the HAP phase up to the highest applied pressure of 4 GPa. For HAP, a unit-cell reduction during compression was evidenced by a reduction in both refined lattice parameters a and c. Both ACP and HAP reverted to their original structures when the pressure was fully released to ambient pressure.展开更多
Similarly to heating, non-thermal technologies like High Hydrostatic Pressure (HHP) are able to affect the native conformation of proteins, causing denaturation, aggregation or gelation. The aim of this work is to eva...Similarly to heating, non-thermal technologies like High Hydrostatic Pressure (HHP) are able to affect the native conformation of proteins, causing denaturation, aggregation or gelation. The aim of this work is to evaluate the effect of product’s chemical-physical characteristics, namely pH and protein concentration, and process parameters, namely pressure level and processing time, on the stability of the structure of a particular allergen, the Bovine Serum Albumin (BSA) as well as to individuate the most appropriate processing conditions to induce protein denaturation and/or aggregation. Different amounts of BSA protein were dissolved in phosphate buffer (50 mM) at three different pH (6, 7 and 8), to obtain concentration levels of 12, 25, 50 and 100 mg/mL. The HHP process was carried out at pressure levels in the range between 700 and 900 MPa and treatment time of 15 - 25 min. The structural characteristics of HHP-treated BSA suspensions were assessed by means of a complete rheological screening (strain sweep, frequency sweep and temperature ramp tests) in dynamic regime. Experimental data demonstrate that the rheological parameters, namely the loss and the storage moduli, increase as pressure levels and processing time increase, especially at higher concentrations, whereas a constant critical strain of about 0.3% is detected. The pH and protein concentration mainly control the denaturation influencing the threshold value of the processing conditions at which the gelation occurs. At processing conditions below the threshold values, however, the structure of BSA can be reversibly damaged.展开更多
Seafood,as a primary high-quality protein source,plays an increasingly vital role in diets around the world,while seafood allergy is a worldwide health problem that affects the quality of life and may even threaten li...Seafood,as a primary high-quality protein source,plays an increasingly vital role in diets around the world,while seafood allergy is a worldwide health problem that affects the quality of life and may even threaten lives.High hydrostatic pressure(HHP),a novel non-thermal processing technology,shows the unique potential in alleviating seafood allergenicity.This comment provides a brief introduction of potential of high hydrostatic pressure in reducing the allergenicity of seafood.展开更多
High hydrostatic pressure assisted extraction (HHPE) has several advantages when compared to traditional extraction methods, which frequently cause degradation and loss of target components and might consume large vol...High hydrostatic pressure assisted extraction (HHPE) has several advantages when compared to traditional extraction methods, which frequently cause degradation and loss of target components and might consume large volumes of environmentally unfriendly solvents. The aim of this study was to develop an assisted extraction method using high hydrostatic pressure (HHPE) and to evaluate both HHPE and conventional extraction methods for β-carotene, antioxidant compounds and vitamin C from cape gooseberry. β-carotene and compounds with antioxidant activity (2,2-diphenyl-1-picrylhydrazyl radical assay (DPPH*) or radical scavenging activity;ferric reducing antioxidant power assay (FRAP)) were extracted using HHPE for 5 min, 10 min and 15 min at 500 MPa, while vitamin C was extracted at 500 MPa for 30 s, 60 s and 90 s. Processing significantly affected (p ≤ 0.05) the β-carotene content of all samples, increasing retention by 8%, 14% and 15% at 500 MPa after 5 min, 10 min and 15 min of HPPE, respectively. The highest antioxidant content determined by DPPH* and FRAP assays was obtained in a sample treated at 500 MPa for 15 min, showing increases of 26% and 51%, respectively, compared with an untreated sample. The ascorbic acid content of fresh cape gooseberry was 26.31 mg·100 g-1. In fact, the ascorbic acid levels were significantly higher for all high-pressure-treated samples compared to this of conventionally extracted sample (p ≤ 0.05), exhibiting increases of 9%, 41% and 53% at 500 MPa after 30 s, 60 s and 90 s of HPPE, respectively. Thus, the application of HHPE produced higher β-carotene content, antioxidant compounds and vitamin C content and required less extraction time compared to other extraction methods. The pharmaceutical and food industries can benefit by using high pressure extraction technology.展开更多
基金supported by the Doctoral Research Foundation of Bohai University (05013/0520bs006)the Science and Technology Project of“Unveiling and Commanding”Liaoning Province (2021JH1/10400033)the Scientific Research Project from Education Department of Liaoning Province (LJ2020010)。
文摘Enzymatic hydrolysis of proteins can enhance their emulsifying properties and antioxidant activities.However,the problem related to the hydrolysis of proteins was the generation of the bitter taste.Recently,high hydrostatic pressure(HHP)treatment has attracted much interest and has been used in several studies on protein modification.Hence,the study aimed to investigate the effects of enzymatic hydrolysis by Corolase PP under different pressure treatments(0.1,100,200,and 300 MPa for 1-5 h at 50℃)on the emulsifying property,antioxidant activity,and bitterness of soybean protein isolate hydrolysate(SPIH).As observed,the hydrolysate obtained at 200 MPa for 4 h had the highest emulsifying activity index(47.49 m^(2)/g)and emulsifying stability index(92.98%),and it had higher antioxidant activities(44.77%DPPH free radical scavenging activity,31.12%superoxide anion radical scavenging activity,and 61.50%copper ion chelating activity).At the same time,the enhancement of emulsion stability was related to the increase of zeta potential and the decrease of mean particle size.In addition,the hydrolysate obtained at 200 MPa for 4 h had a lower bitterness value and showed better palatability.This study has a broad application prospect in developing food ingredients and healthy foods.
基金supported by grants from the National Natural Science Foundation of China(No.82270812)Medical Innovation and Transformation Incubation Project of Tongji Hospital(No.2022ZHFY11).
文摘Objective Bladder outlet obstruction(BOO)results in significant fibrosis in the chronic stage and elevated bladder pressure.Piezo1 is a type of mechanosensitive(MS)channel that directly responds to mechanical stimuli.To identify new targets for intervention in the treatment of BOO-induced fibrosis,this study investigated the impact of high hydrostatic pressure(HHP)on Piezo1 activity and the progression of bladder fibrosis.Methods Immunofluorescence staining was conducted to assess the protein abundance of Piezo1 in fibroblasts from obstructed rat bladders.Bladder fibroblasts were cultured under normal atmospheric conditions(0 cmH_(2)O)or exposed to HHP(50 cmH_(2)O or 100 cmH_(2)O).Agonists or inhibitors of Piezo1,YAP1,and ROCK1 were used to determine the underlying mechanism.Results The Piezo1 protein levels in fibroblasts from the obstructed bladder exhibited an elevation compared to the control group.HHP significantly promoted the expression of various pro-fibrotic factors and induced proliferation of fibroblasts.Additionally,the protein expression levels of Piezo1,YAP1,ROCK1 were elevated,and calcium influx was increased as the pressure increased.These effects were attenuated by the Piezo1 inhibitor Dooku1.The Piezo1 activator Yoda1 induced the expression of pro-fibrotic factors and the proliferation of fibroblasts,and elevated the protein levels of YAP1 and ROCK1 under normal atmospheric conditions in vitro.However,these effects could be partially inhibited by YAP1 or ROCK inhibitors.
文摘Response surface methodology (RSM) was employed in the present work and a second orderquadratic equation for high hydrostatic pressure (HHP) inactivation was built. Theadequacy of the model equation for predicting the optimum response values was verifiedeffectively by the validation data. Effects of temperature, pressure, and pressureholding time on HHP inactivation of Escherichia coli ATCC 8739 were explored. Byanalyzing the response surface plots and their corresponding contour plots as well assolving the quadratic equation, the optimum process parameters for inactivation E. coliof six log cycles were obtained as: temperature 32.2℃, pressure 346.4 MPa, and pressureholding time 12.6min.
基金Supported by the National Natural Science Foundation of China(Nos.91751108,91751202,41806174,41506147)the National Key Research and Development Program of China(Nos.2016YFC0302502,2016YFC0304905,2018YFC0309904)+1 种基金the Sanya Municipal(Nos.2018YD01,2018YD02)the grant for LIA-Mag MC from the Centre National de la Recherche Scientifique
文摘Trimethylamine N-oxide(TMAO)is one of the most important nutrients for bacteria in the deep-sea environment and is capable of improving pressure tolerance of certain bacterial strains.To assess the impact of TMAO on marine microorganisms,especially those dwelling in the deep-sea environment,we analyzed the bacterial community structure of deep-sea sediments after incubated under different conditions.Enrichments at 50 MPa and 0.1 MPa revealed that TMAO imposed a greater influence on bacterial diversity and community composition at atmospheric pressure condition than that under high hydrostatic pressure(HHP).We found that pressure was the primary factor that determines the bacterial community.Meanwhile,in total,238 bacterial strains were isolated from the enrichments,including 112 strains a ffiliated to 16 genera of 4 phyla from the Yap Trench and 126 strains a ffiliated to 11 genera of 2 phyla from the Mariana Trench.Treatment of HHP reduced both abundance and diversity of isolates,while the presence of TMAO mainly af fected the diversity of isolates obtained.In addition,certain genera were isolated only when TMAO was supplemented.Taken together,we demonstrated that pressure primarily defines the bacterial community and culturable bacterial isolates.Furthermore,we showed for the first time that TMAO had distinct influences on bacterial community depending on the pressure condition.The results enriched the understanding of the significance of TMAO in bacterial adaptation to the deep-sea environment.
基金supported financially by the National Natural Science Foundation of China (Grant No.31760468 and32060515)Inner Mongolia Autonomous Region Science and Technology Plan Project (No.2020GG0064)
文摘As a non-thermal processing technology,high hydrostatic pressure(HHP)can be used for starch modification without affecting the quality and flavour constituents.The effect of HHP on starch is closely related to the treatment time of HHP.In this paper,we investigated the impacts of HHP treatment time(0,5,10,15,20,25,30 min)on the microstructure,gelatinization and thermal properties as well as in vitro digestibility of oat starch by scanning electron microscopy,X-ray diffraction,Fourier transform infrared spectroscopy,13C NMR and differential scanning calorimeter.Results showed that 5-min HHP treatment led to deformation and decreases in short-range ordered and doublehelix structures of oat starch granules,and further extending the treatment time to 15 min or above caused the formation of a gelatinous connection zone,increase of particle size,disintegration of short-range ordered and double-helix structures,and crystal structure change from A type to V type,indicating gelatinization occurred.Longer treatment time also resulted in the reduction in both the viscosity and the stability of oat starch.These indicated that HHP treatment time greatly influenced the microstructure of oat starch,and the oat starch experienced crystalline destruction(5 min),crystalline disintegration(15 min)and gelatinization(>15 min)during HHP treatment.Results of in vitro digestibility showed that the rapidly digestible starch(RDS)content declined first after treatment for 5 to 10 min then rose with the time extending from 15 to 30 min,indicating that longer pressure treatment time was unfavourable to the health benefits of oat starch for humans with diabetes and cardiovascular disease.Therefore,the 500-MPa treatment time for oat starch is recommended not more than 15 min.This study provides theoretical guidance for the application of HHP technology in starch modification and development of health foods.
基金This work was supported by the National Natural Sci-ence Foundation of China(30070426)the Program of Agri-cultural Office of Chinese Acdemy of Sciencesthe State Key Basic Research and Development Plan of China(G1 998010100).
文摘Three mutants of rice (Oryza sativa L. ), Mutant 1, Mutant 2 and Mutant 3, which were selected by high hydrostatic pressure (75 MPa), and their parent Yuexiangzhan were used to study the changes in chlorophyll fluorescence during different growth stages. In all the three mutants, the function of PSⅡ was improved, F_v/F_m ratio of mutants increased compared to their parent at tillering and heading stage, and ΦPSⅡ also improved except for Mutant 2 at heading stage. Similar to their parent, the mutants exhibited slight photoinhibition at noon and almost complete recovery to initial levels of 6:00 after 18:00 at heading stage. At milking stage, the photoinhibition in the mutants was obvious, and recovered rapidly compared to the parent. Yields of individual plant and grain/straw ratio were also higher in three mutants than the parent. Results indicated that characteristics of chlorophyll fluorescence in leaves of mutants and their photoinhibition in the field had changed. It is suggested that high hydrostatic pressure induction could be applied as a new effective approach in high-yield rice breeding in the future.
基金Supported by China Postdoctoral Science Foundation(No.2014M551502)National Natural Science Foundation of China(No.31301599)
文摘High hydrostatic pressure（HHP） processing is applied to a Konjac glucomannan（KGM）-casein（CS） mixture to explore the changes in the mixture＇s properties and microstructures.The mixture＇s viscosity increases by -18.1% at low HHP（200 MPa） and decreases by about 5.3-31.7% at high HHP（600 MPa）.Scanning electron microscopy analysis shows that low HHP induces a denser and more compact structure,and high HHP leads to a porous and reticular structure.X-ray diffraction shows that the mixture is amorphous without dramatic changes; only some small crystalline peaks appear under excessive pressure.Fourier transform infrared analysis indicates that the non-covalent interactions（hydrogen bonds,etc.） are probably the most important factors for the modification of mixture properties.Bonding enhances under low pressure,and weakens with increasing pressure and time.
文摘The effects of high hydrostatic pressure （HHP） treatment on sea cucumber qualities, such as shelf-life, autoenzyme, total volatile basic nitrogen （TVB-N）, mucopolysaccha ride and protein, were investigated experimentally. The shelf-life of sea cucumber was greatly prolonged by HHP treatment. High pressure treatment of sea cucumber significantly reduced the activity of autoenzyme at 550 MPa. The TVB-N content was 8.4 mg/100 g in the HHP-treated samples after 38 days＇ storage at 4 ~C, while it had already reached 11.2 mg/100 g in the untreated ones after 5 days＇ storage under the same condition. The relative mucopolysaccharide content of the HHP-treated samples was 94.3%, while that of the heat-treated ones was only 35.5%. The sodium dodecyl sulfate polyacrylamide gel electrophoresis （SDS-PAGE）, Differential scanning calorimetric （DSC）, ANS fluorescence probe method and fourier-transform infrared （FTIR） spectroscopy results indicated some changes in protein subunits, denaturation, surface hydrophobicity and secondary structure of sea cucumber protein. This study has provided complementary information of pressure-induced structural changes on both the molecular and the sub-molecular level of sea cucumber protein.
文摘The influences of ultra-high hydrostatic pressure treatment on foaming and physical properties (solubility, hydrophobicity and sulfhydryl content) of egg white were investigated. A pressure range of 0-500 MPa, time range of 0-20 min and pH range of 7.5-8.5 were selected. The foaming property of egg white is improved by 350Mpa and 10min. The treatment resulted in in- crease of sulfhydryl content of egg white, while solubility and hydrophobicity were significantly decreased.
基金supported by grant from China Postdoctoral Science Foundation to Dr. Chuyi Liu (No. 2016 M592251)
文摘Alaska pollock is an important protein source which is extensively used in the food industry. Pollock protein isolates(PPI) with significantly enriched protein contents could be prepared using isoelectric solubilization/precipitation(ISP) processing; however, the functional properties of this process is limited by the large amount of water-insoluble proteins. In this study, we investigated the influence of high hydrostatic pressure(HHP) treatment on the solubility and structural changes of PPI. PPI obtained using ISP is treated with hydrostatic pressures of 200, 300, 400, and 500 MPa for up to 15 min, and the HHP-treated samples were observed to exhibit significantly improved solubilities. Further biochemical assays reveal that the continuous HHP treatments reduce the contents of free sulfhydryl groups and promote the formation of macromolecules with better water solubilities, which may induce the solubility improvements of the HHP-treated PPI. Our results indicate that HHP can be utilized to effectively prepare highly water-soluble Alaska pollock protein in food processing.
基金funded through an FRDF funding (Grant 3702239) provided by the University of Auckland, New Zealand
文摘The changes in the crystal structures of synthetically prepared amorphous calcium phosphate（ACP） and hydroxyapatite（HAP） in water（1：1 mass ratio） were studied by synchrotron X-ray diffraction（XRD） under ultra-high hydrostatic pressures as high as 2.34 GPa for ACP and 4 GPa for HAP. At ambient pressure, the XRD patterns of the ACP and HAP samples in capillary tubes and their environmental scanning electron micrographs indicated amorphous and crystalline characteristics for ACP and HAP, respectively. At pressures greater than 0.25 GPa, an additional broad peak was observed in the XRD pattern of the ACP phase, indicating a partial phase transition from an amorphous phase to a new high-pressure amorphous phase. The peak areas and positions of the ACP phase, as obtained through fitting of the experimental data, indicated that the ACP exhibited increased pseudo-crystalline behavior at pressures greater than 0.96 GPa. Conversely, no structural changes were observed for the HAP phase up to the highest applied pressure of 4 GPa. For HAP, a unit-cell reduction during compression was evidenced by a reduction in both refined lattice parameters a and c. Both ACP and HAP reverted to their original structures when the pressure was fully released to ambient pressure.
文摘Similarly to heating, non-thermal technologies like High Hydrostatic Pressure (HHP) are able to affect the native conformation of proteins, causing denaturation, aggregation or gelation. The aim of this work is to evaluate the effect of product’s chemical-physical characteristics, namely pH and protein concentration, and process parameters, namely pressure level and processing time, on the stability of the structure of a particular allergen, the Bovine Serum Albumin (BSA) as well as to individuate the most appropriate processing conditions to induce protein denaturation and/or aggregation. Different amounts of BSA protein were dissolved in phosphate buffer (50 mM) at three different pH (6, 7 and 8), to obtain concentration levels of 12, 25, 50 and 100 mg/mL. The HHP process was carried out at pressure levels in the range between 700 and 900 MPa and treatment time of 15 - 25 min. The structural characteristics of HHP-treated BSA suspensions were assessed by means of a complete rheological screening (strain sweep, frequency sweep and temperature ramp tests) in dynamic regime. Experimental data demonstrate that the rheological parameters, namely the loss and the storage moduli, increase as pressure levels and processing time increase, especially at higher concentrations, whereas a constant critical strain of about 0.3% is detected. The pH and protein concentration mainly control the denaturation influencing the threshold value of the processing conditions at which the gelation occurs. At processing conditions below the threshold values, however, the structure of BSA can be reversibly damaged.
文摘Seafood,as a primary high-quality protein source,plays an increasingly vital role in diets around the world,while seafood allergy is a worldwide health problem that affects the quality of life and may even threaten lives.High hydrostatic pressure(HHP),a novel non-thermal processing technology,shows the unique potential in alleviating seafood allergenicity.This comment provides a brief introduction of potential of high hydrostatic pressure in reducing the allergenicity of seafood.
基金The authors wish to acknowledge the financial support of Fondecyt Regular n°1120069CEAZA and the Research Department of Universidad de La Serena(DIULS).
文摘High hydrostatic pressure assisted extraction (HHPE) has several advantages when compared to traditional extraction methods, which frequently cause degradation and loss of target components and might consume large volumes of environmentally unfriendly solvents. The aim of this study was to develop an assisted extraction method using high hydrostatic pressure (HHPE) and to evaluate both HHPE and conventional extraction methods for β-carotene, antioxidant compounds and vitamin C from cape gooseberry. β-carotene and compounds with antioxidant activity (2,2-diphenyl-1-picrylhydrazyl radical assay (DPPH*) or radical scavenging activity;ferric reducing antioxidant power assay (FRAP)) were extracted using HHPE for 5 min, 10 min and 15 min at 500 MPa, while vitamin C was extracted at 500 MPa for 30 s, 60 s and 90 s. Processing significantly affected (p ≤ 0.05) the β-carotene content of all samples, increasing retention by 8%, 14% and 15% at 500 MPa after 5 min, 10 min and 15 min of HPPE, respectively. The highest antioxidant content determined by DPPH* and FRAP assays was obtained in a sample treated at 500 MPa for 15 min, showing increases of 26% and 51%, respectively, compared with an untreated sample. The ascorbic acid content of fresh cape gooseberry was 26.31 mg·100 g-1. In fact, the ascorbic acid levels were significantly higher for all high-pressure-treated samples compared to this of conventionally extracted sample (p ≤ 0.05), exhibiting increases of 9%, 41% and 53% at 500 MPa after 30 s, 60 s and 90 s of HPPE, respectively. Thus, the application of HHPE produced higher β-carotene content, antioxidant compounds and vitamin C content and required less extraction time compared to other extraction methods. The pharmaceutical and food industries can benefit by using high pressure extraction technology.
